Improve the missing plugin error to include the full name of the binary

CHANGELOG_PENDING.md

@@ -11,10 +11,13 @@
 
 - [cli/plugins] Add support for downloading plugin from private Pulumi GitHub releases. This also drops the use of the `GITHUB_ACTOR` and `GITHUB_PERSONAL_ACCESS_TOKEN` environment variables for authenticating to github. Only `GITHUB_TOKEN` is now used, but this can be set to a personal access token.
   [#9185](https://github.com/pulumi/pulumi/pull/9185)
-  
+
 - [cli] - Speed up `pulumi stack --show-name` by skipping unneeded snapshot loading.
   [#9199](https://github.com/pulumi/pulumi/pull/9199)
 
+- Improved error message for missing plugins.
+  [#5208](https://github.com/pulumi/pulumi/pull/5208)
+
 ### Bug Fixes
 
 - [sdk/nodejs] - Fix uncaught error "ENOENT: no such file or directory" when an error occurs during the stack up.

sdk/go/common/resource/plugin/analyzer_plugin.go

@@ -58,12 +58,8 @@ func NewAnalyzer(host Host, ctx *Context, name tokens.QName) (Analyzer, error) {
 		workspace.AnalyzerPlugin, strings.Replace(string(name), tokens.QNameDelimiter, "_", -1), nil)
 	if err != nil {
 		return nil, rpcerror.Convert(err)
-	} else if path == "" {
-		return nil, workspace.NewMissingError(workspace.PluginInfo{
-			Kind: workspace.AnalyzerPlugin,
-			Name: string(name),
-		})
 	}
+	contract.Assert(path != "")
 
 	plug, err := newPlugin(ctx, ctx.Pwd, path, fmt.Sprintf("%v (analyzer)", name),
 		[]string{host.ServerAddr(), ctx.Pwd}, nil /*env*/)

sdk/go/common/resource/plugin/langruntime_plugin.go

@@ -50,13 +50,10 @@ func NewLanguageRuntime(host Host, ctx *Context, runtime string,
 		workspace.LanguagePlugin, strings.Replace(runtime, tokens.QNameDelimiter, "_", -1), nil)
 	if err != nil {
 		return nil, err
-	} else if path == "" {
-		return nil, workspace.NewMissingError(workspace.PluginInfo{
-			Kind: workspace.LanguagePlugin,
-			Name: runtime,
-		})
 	}
 
+	contract.Assert(path != "")
+
 	args, err := buildArgsForNewPlugin(host, ctx, options)
 	if err != nil {
 		return nil, err

sdk/go/common/resource/plugin/provider_plugin.go

@@ -81,14 +81,10 @@ func NewProvider(host Host, ctx *Context, pkg tokens.Package, version *semver.Ve
 		workspace.ResourcePlugin, strings.Replace(string(pkg), tokens.QNameDelimiter, "_", -1), version)
 	if err != nil {
 		return nil, err
-	} else if path == "" {
-		return nil, workspace.NewMissingError(workspace.PluginInfo{
-			Kind:    workspace.ResourcePlugin,
-			Name:    string(pkg),
-			Version: version,
-		})
 	}
 
+	contract.Assert(path != "")
+
 	// Runtime options are passed as environment variables to the provider.
 	env := os.Environ()
 	for k, v := range options {

sdk/go/common/workspace/plugins.go

@@ -122,25 +122,33 @@ func parsePluginDownloadURLOverrides(overrides string) (pluginDownloadOverrideAr
 type MissingError struct {
 	// Info contains information about the plugin that was not found.
 	Info PluginInfo
+	// includeAmbient is true if we search $PATH for this plugin
+	includeAmbient bool
 }
 
 // NewMissingError allocates a new error indicating the given plugin info was not found.
-func NewMissingError(info PluginInfo) error {
+func NewMissingError(info PluginInfo, includeAmbient bool) error {
 	return &MissingError{
-		Info: info,
+		Info:           info,
+		includeAmbient: includeAmbient,
 	}
 }
 
 func (err *MissingError) Error() string {
+	includePath := ""
+	if err.includeAmbient {
+		includePath = " or on your $PATH"
+	}
+
 	if err.Info.Version != nil {
-		return fmt.Sprintf("no %[1]s plugin '%[2]s-v%[3]s' found in the workspace or on your $PATH, "+
+		return fmt.Sprintf("no %[1]s plugin 'pulumi-%[1]s-%[2]s' found in the workspace at version v%[3]s%[4]s, "+
 			"install the plugin using `pulumi plugin install %[1]s %[2]s v%[3]s`",
-			err.Info.Kind, err.Info.Name, err.Info.Version)
+			err.Info.Kind, err.Info.Name, err.Info.Version, includePath)
 	}
 
-	return fmt.Sprintf("no %s plugin '%[1]s' found in the workspace or on your $PATH, "+
+	return fmt.Sprintf("no %[1]s plugin 'pulumi-%[1]s-%[2]s' found in the workspace%[3]s, "+
 		"install the plugin using `pulumi plugin install %[1]s %[2]s`",
-		err.Info.Kind, err.Info.Name)
+		err.Info.Kind, err.Info.Name, includePath)
 }
 
 // PluginSource deals with downloading a specific version of a plugin, or looking up the latest version of it.
@@ -1042,7 +1050,8 @@ func GetPluginPath(kind PluginKind, name string, version *semver.Version) (strin
 	// If we have a version of the plugin on its $PATH, use it, unless we have opted out of this behavior explicitly.
 	// This supports development scenarios.
 	optOut, isFound := os.LookupEnv("PULUMI_IGNORE_AMBIENT_PLUGINS")
-	if !(isFound && cmdutil.IsTruthy(optOut)) || isBundledLangauge {
+	includeAmbient := !(isFound && cmdutil.IsTruthy(optOut)) || isBundledLangauge
+	if includeAmbient {
 		filename = (&PluginInfo{Kind: kind, Name: name, Version: version}).FilePrefix()
 		if path, err := exec.LookPath(filename); err == nil {
 			logging.V(6).Infof("GetPluginPath(%s, %s, %v): found on $PATH %s", kind, name, version, path)
@@ -1092,7 +1101,7 @@ func GetPluginPath(kind PluginKind, name string, version *semver.Version) (strin
 				Name:    name,
 				Kind:    kind,
 				Version: version,
-			})
+			}, includeAmbient)
 		}
 		match = &candidate
 	} else {
@@ -1136,7 +1145,11 @@ func GetPluginPath(kind PluginKind, name string, version *semver.Version) (strin
 		return matchDir, matchPath, nil
 	}
 
-	return "", "", nil
+	return "", "", NewMissingError(PluginInfo{
+		Name:    name,
+		Kind:    kind,
+		Version: version,
+	}, includeAmbient)
 }
 
 // SortedPluginInfo is a wrapper around PluginInfo that allows for sorting by version.

sdk/go/common/workspace/plugins_test.go

@@ -726,3 +726,80 @@ func TestParsePluginDownloadURLOverride(t *testing.T) {
 		})
 	}
 }
+
+func TestMissingErrorText(t *testing.T) {
+	t.Parallel()
+
+	v1 := semver.MustParse("0.1.0")
+	tests := []struct {
+		Name           string
+		Plugin         PluginInfo
+		IncludeAmbient bool
+		ExpectedError  string
+	}{
+		{
+			Name: "ResourceWithVersion",
+			Plugin: PluginInfo{
+				Name:    "myplugin",
+				Kind:    ResourcePlugin,
+				Version: &v1,
+			},
+			IncludeAmbient: true,
+			ExpectedError: "no resource plugin 'pulumi-resource-myplugin' found in the workspace " +
+				"at version v0.1.0 or on your $PATH, install the plugin using `pulumi plugin install resource myplugin v0.1.0`",
+		},
+		{
+			Name: "ResourceWithVersion_ExcludeAmbient",
+			Plugin: PluginInfo{
+				Name:    "myplugin",
+				Kind:    ResourcePlugin,
+				Version: &v1,
+			},
+			IncludeAmbient: false,
+			ExpectedError: "no resource plugin 'pulumi-resource-myplugin' found in the workspace " +
+				"at version v0.1.0, install the plugin using `pulumi plugin install resource myplugin v0.1.0`",
+		},
+		{
+			Name: "ResourceWithoutVersion",
+			Plugin: PluginInfo{
+				Name:    "myplugin",
+				Kind:    ResourcePlugin,
+				Version: nil,
+			},
+			IncludeAmbient: true,
+			ExpectedError: "no resource plugin 'pulumi-resource-myplugin' found in the workspace " +
+				"or on your $PATH, install the plugin using `pulumi plugin install resource myplugin`",
+		},
+		{
+			Name: "ResourceWithoutVersion_ExcludeAmbient",
+			Plugin: PluginInfo{
+				Name:    "myplugin",
+				Kind:    ResourcePlugin,
+				Version: nil,
+			},
+			IncludeAmbient: false,
+			ExpectedError: "no resource plugin 'pulumi-resource-myplugin' found in the workspace" +
+				", install the plugin using `pulumi plugin install resource myplugin`",
+		},
+		{
+			Name: "LanguageWithoutVersion",
+			Plugin: PluginInfo{
+				Name:    "dotnet",
+				Kind:    LanguagePlugin,
+				Version: nil,
+			},
+			IncludeAmbient: true,
+			ExpectedError: "no language plugin 'pulumi-language-dotnet' found in the workspace " +
+				"or on your $PATH, install the plugin using `pulumi plugin install language dotnet`",
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.Name, func(t *testing.T) {
+			t.Parallel()
+			err := NewMissingError(tt.Plugin, tt.IncludeAmbient)
+			assert.Equal(t, tt.ExpectedError, err.Error())
+		})
+	}
+}